Romans in desolate places – Tomen y Mur

On the bleak wind swept slopes above Llyn Trawsfynydd in Meirionydd lay the remains of a Roman fort and amphitheatre. It’s an unexpected find on the slopes of Mynydd Maentwrog, among the fields and sheep, surrounded and over looked by the rugged peaks of the Rhinog Fach and Rhionog Fawr brooding along the horizon to the west. This must have been a forbidding posting for the soldiers. It certainly was today as I took a brief break on a business trip to Bangor, leaving Aunty behind decorTing the bedroom. In fact it was freezing, with a stiff northerly wind trying to give frostbite to my ears.


The Roman invasion and occupation of Britain was not a straight forward affair despite rapid advances across what is now Southern, mid and western England. Raids by the Deceangli tribe into the Modlands led to Roman counter attacks into North Wales. But the main concern was the long campaign against the stubborn resistance by the Silures of South Wales and the Ordovices of mid Wales, possibly led by Caratacus. 

The Welsh landscape was a significant factor in assisting the resistance against the Roman army. The narrow valleys, dense woodland and steep hills was more suited to guerrilla warfare than the staged battles that the organised legions preferred.

The first two major campaigns into Wales in 47 and 60 AD were not fully successful because of uprisings by conquered tribes elsewhere in England. The disruption caused by Boudicca, closely followed by a change of Emporer delayed any further attempts at conquest in Wales for another 10 years. The final invasion was completed around 77AD with the fall of Angelsy and the destruction of the sacred Druid groves, finally ending resistance from the Welsh tribes.

Tomen y Mur was possibly built in 77 or 78 AD as part of Agricola’s early campaigns (2). At this time it was probably mainly constructed out of timber, covering an area of approximately 1.7 ha. It was part of a campaign to control the Ordovices tribe, who actively resisted the Roman rule. Agricola’s response was a brutal campaign that suppressed, and almost wiped out the Ordivices. Agricola built a series forts like Tomen y Mur to control the Welsh tribes. The location, though remote, stands beside a crossing of four Roman roads. 

The timber fort housed about 1000 cavalry initially, but early in the 2nd century conditions must have eased, for the fort was rebuilt in stone to accommodate a much smaller force of around 500 infantry. Need for a military presence must have lessened enormously over the following few decades, for the fort was abandoned around 140 AD.

It includes the playing-card plan of the fort (A), the line of defence to reduce the size of the fort and a Norman motte dating from a millennium later (B). The headquarters building (C) and barrack blocks can be seen. Other classic military features include a parade ground (E), practice camps (J), an amphitheatre (D), a bathhouse (G), an annexe (K), water supply leats (I) and bridge abutments (H). The tribunal (F) from which officers oversaw the troops on the parade ground may have originated as a geological feature (1).

After the Romans left the area, the fort probably continued to be important into the medieval period, because a fifth century gravestone has been uncovered there. The Cunedda family line of Welsh princes may have moved into the fort after the Romans, for it is mentioned in Welsh folklore, particularly the Mabinogion. Tomen-y-Mur was taken over by the Normans in the late eleventh or early twelfth Century, when the defences would have been refortified. The ‘Tomen’ which is the now dominant Norman castle motte, was probably built at this time, when William Rufus was sent to counter the Welsh insurgency in 1095, although he didn’t stay long.

Nine stones inscribed with Latin were found in the structure of Harlech Castle, and it  is thought these come from Tomen y Mur (2). Now there’s cycling for you. Each stone depicts in ‘paces’ various lengths of completed fortress wall, and the ‘centuria’ or unit of 100 men that built it. It is therefore speculated that most of the shaped stone from the fortress of Tomen-y-Mur was used to construct Harlech Castle from 1283.

The area around Tomen Y Mur also figure in the Mabinogion, a set of ancient Welsh tales that were handed down the generations via the bardic tradition before being written down in the 12-13th centuries (3). Lleu Llaw Gyffes was the local ruler and great friend of Math. When Lleu left his wife alone, to visit Math in Arfon, Blodeuwedd found the loneliness of Tomen y Mur difficult to cope with. To help pass the time, Blodeuwedd kept company with Gronw Pebyr, a young Lord from from Caer Gai by Bala. After a while they fell in love with each and as they gazed into the mountains they plotted Lleu’s death. Now this was not an easy thing to do because Lleu could not be slain inside a house, or outside, nor on horseback or afoot.  No weapon would kill him save a spear which would take a year to forge, and that only when “folk were at Mass on Sunday”.

Eventually the lovers found a way and started to plot Lleu’s death. When Lleu was taking a dip in the Cynfal river Gronw Pebyr shot the poisoned spear through him. At once Lleu became an eagle soaring high, and was seen no more. Later through the magic of the Children of the Don, Lleu was restored, and good physicians of Gwynedd brought him back to health. Lleu then made for His home at Toem y Mur. But hearing of his return Blodeuwedd and her maidens fled north towards the mountains where Gwydion caught up with them and changed her into an owl, because of her dishonour and her evil never to show her face again by day. The maidens rushed headlong into a lake called after them, Llyn Morwynion, the same in which some or all, of the abducted women of Clwyd chose to end their lives.

Gronw came to the sticky end he well deserved. For a year he had subdued and ruled over Lleu’s land. After returning to Tomen y Mur, Lleu demanded revenge. Gronw Offered as reparation of all the gold and silver in Penllyn. However Lleu refused, instead bidding him to go to the spot where Gronw had attempted Lleus murder with the poisoned spear. Lleu followed and when his enemy faced him, his back against a rock on the Cynfal banks, the hero hurled the spear pinning Gronw to what is still called Llech Ronw.


1: Driver, T. And Browne, D. (2002) Tomen y Mur, Roman Military Complex: Description of the site produced for a 2002 RCAHMW Commissioners visit. Royal Commission on the Ancient and Historical Monuments of Wales.

2: Symons, S. (2009) Fortresses and Treasures of Roman Wales. DB Publishing.

3: Davies,S. (2007) The Mabinogion. Oxford Univeristy Press.


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